Heterogeneous rock mass classification by means of the geological strength index: the San Mauro formation (Cilento, Italy)

2011 ◽  
Vol 70 (4) ◽  
pp. 585-593 ◽  
Author(s):  
P. Budetta ◽  
M. Nappi
Keyword(s):  
Rock Mass ◽  
Rock Mass Classification ◽  
Geological Strength Index ◽  
Strength Index ◽  
Heterogeneous Rock ◽  
Mass Classification

scholarly journals Study of Rock Mass Rating (RMR) and Geological Strength Index (GSI) Correlations in Granite, Siltstone, Sandstone and Quartzite Rock Masses

2021 ◽  
Vol 11 (8) ◽  
pp. 3351
Author(s):  
Gabor Somodi ◽  
Neil Bar ◽  
László Kovács ◽  
Marco Arrieta ◽  
Ákos Török ◽  
...  
Keyword(s):  
Rock Mass ◽  
Linear Equations ◽  
Geological Strength Index ◽  
Gold Mine ◽  
Strength Index ◽  
Comprehensive Understanding ◽  
Rock Types ◽  
Mass Classification ◽  
Waste Repository ◽  
And Performance

A comprehensive understanding of geological, structural geological, hydrogeological and geotechnical features of the host rock are essential for the design and performance evaluation of surface and underground excavations. The Hungarian National Radioactive Waste Repository (NRWR) at Bátaapáti is constructed in a fractured granitic formation, and Telfer Gold Mine in Australia is excavated in stratified siltstones, sandstones and quartzites. This study highlights relationships between GSI chart ratings and calculated GSI values based on RMR rock mass classification data. The paper presents linear equations for estimating GSI from measured RMR89 values. Correlations between a and b constants were analyzed for different rock types, at surface and subsurface settings.

scholarly journals Recommendations of excavation and support systems of Pamukkulu Dam diversion tunnel based on correlation of rock mass classification between RMR and GSI

2021 ◽  
Vol 325 ◽  
pp. 04002
Author(s):  
Dico Nasrulloh ◽  
Agung Setianto ◽  
I Gde Budi Indrawan
Keyword(s):  
Rock Mass ◽  
Support System ◽  
Rock Mass Classification ◽  
Geological Strength Index ◽  
Class Iii ◽  
Tunnel Face ◽  
Diversion Tunnel ◽  
Engineering Research ◽  
Mass Classification ◽  
Drill And Blast

This paper presents the results of geological engineering research conducted to determine the character of rock masses, recommendations of tunnel excavation method and support system based on standup time estimates in unsuported conditions. The investigation was conducted by observing rock mass quality based on the newest bore log sample test results in 2019 using Rock Mass Rating (RMR) and Geological Strength Index (GSI) rock mass classification. The results showed that area consist of lithology in the form of porphyryc lava basalt and pyroclastic volcanic breccia. Rock mass has a slightly weathering alteration rates. Intact rocks have Uniaxial Compressive Strength (UCS) values ranging from 100-250 Mpa to >250 Mpa and are a category of strong rocks. Rock mass has fair to good rock quality class III-II based on RMR values between 53-69, GSI values between 48-64. The roof span required is obtained from the tunnel planning roof span of 10 meter, with a stand-up time of 70 hours without support system and immediate collapse for 5 days. The recommended excavation methods are excavation by drill and blast on top heading and bench: 1,5-3 meter advance in top heading tunnel face, and then can be recommended support system using rock bolts (20 mm diameter, fullly bonded): systematic bolts 4 meter long, spaced 1,5-2 meter in crown and bench with wiremesh in crown then shotcrete: 50-100 mm in crown, and 30 mm in sides, without steel ribs support.

scholarly journals Estimating TBM Specific Energy by Employing the Rock Mass Strain Energy, A Case Study: Karaj – Tehran Water Conveyance Tunnel located in Iran

2021 ◽  
Author(s):  
Majid Mirahmadi
Keyword(s):  
Rock Mass ◽  
Specific Energy ◽  
Strain Energy ◽  
Strain Curve ◽  
Rock Mass Classification ◽  
Geological Strength Index ◽  
Peak Strain ◽  
Water Conveyance ◽  
Mass Classification ◽  
Water Conveyance Tunnel

Abstract Recently energy costs are increasing so it is critical to master the challenge of energy efficiency. Energy consumption for drilling in tunnel Boring Machines (TBMs) is mainly determined by the specific energy. Specific energy is the amount of energy needed to excavate a unit volume of rock mass and is considered one of the important parameters used for performance prediction of TBMs. This study tries to apply the strain energy of a rock mass to develop a new method for foretelling specific energy for TBM. The area under complete stress–strain curve is known as strain energy which is pertinent to the rock mass behavior, pre and post failure properties, peak strain and post peak strain. In this study statistical analysis performed through collected actual data from Karaj Tehran Water Conveyance Tunnel revealed a new relationship between the specific energy used by TBM (SE) and the strain energy. For more detailed study the rock mass classification is performed with respect to the geological strength index and all geological units are then classified in three classes and the specific energy of TBM is predicted based on the strain energy of rock mass for each three classes. The results reveals that two parameters of the specific energy and the strain energy are in a direct relation whose correlation is increased with considering the rock mass classification based on the post peak behavior of rock mass.

scholarly journals Qualifying the geotechnical and hydrological characteristic of the Bandawaya stream valley – Northern Iraq

2020 ◽  
Vol 29 (3) ◽  
pp. 319-331
Author(s):  
Azealdeen Al-Jawadi ◽  
Yousra Abdul Baqi ◽  
Ali Sulaiman
Keyword(s):  
Rock Mass ◽  
Classification Systems ◽  
Geological Strength Index ◽  
Strength Index ◽  
Northern Iraq ◽  
Supplementary Irrigation ◽  
Mass Classification ◽  
Weak Zones ◽  
Q System ◽  
Geotechnical Studies

In northern Iraq, countless non-abuse stream valleys can be used to store water for a variety of purposes; domestic, supplementary irrigation, and recharging groundwater. Bandawaya is one of the stream valleys, which form the first perspective has excellent quality. The location of the suggested dam has been evaluated by hydrological and geotechnical studies. Geotechnical studies included measurement of all the parameters related to the rock mass classification for evaluation based on four classification systems, which are the Q-System, the rock mass rating (RMR), the geological strength index (GSI), and the rock mass index (RMi). The classification results indicated that the rocks of the valley are good for constructing a dam on them, with some weak zones that may affect the integrity of the dam, which the study recommended treating before starting the construction of the dam. According to preliminary studies on different dam’s heights the qualification demonstrates an excellent choice of the site. Four stream orders are recognized, dendritic pattern in the southern part of the watershed, and trellised in the northern part. Three heights assumed to the proposed dam 450, 460, 470 m a.s.l. with 640,764; 3429,787; 8,590,763 m3 storage capacity respectively. According to the Q-System, the RMR, the GSI, and the RMi, the rock mass of the study area is evaluated. The findings illustrate the excellent selection by geotechnical, hydrological, and engineering features of the dam place.

scholarly journals Influence of the groundwater level on the bearing capacity of shallow foundations on the rock mass

2021 ◽  
Author(s):  
Ana Alencar ◽  
Rubén Galindo ◽  
Svetlana Melentijevic
Keyword(s):  
Rock Mass ◽  
Bearing Capacity ◽  
Groundwater Level ◽  
Sensitivity Study ◽  
Shallow Foundations ◽  
Unit Weight ◽  
Geological Strength Index ◽  
Strength Index ◽  
Mass Type

AbstractThe presence of the groundwater level (GWL) at the rock mass may significantly affect the mechanical behavior, and consequently the bearing capacity. The water particularly modifies two aspects that influence the bearing capacity: the submerged unit weight and the overall geotechnical quality of the rock mass, because water circulation tends to clean and open the joints. This paper is a study of the influence groundwater level has on the ultimate bearing capacity of shallow foundations on the rock mass. The calculations were developed using the finite difference method. The numerical results included three possible locations of groundwater level: at the foundation level, at a depth equal to a quarter of the footing width from the foundation level, and inexistent location. The analysis was based on a sensitivity study with four parameters: foundation width, rock mass type (mi), uniaxial compressive strength, and geological strength index. Included in the analysis was the influence of the self-weight of the material on the bearing capacity and the critical depth where the GWL no longer affected the bearing capacity. Finally, a simple approximation of the solution estimated in this study is suggested for practical purposes.

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